The purpose of this contract is to provide the AIDS Program of the NIAID with a contractor capable of producing reagents for research on HTLV-III/LAV [Note: The International Committee on Taxonomy of Viruses has recommended the term human immunodeficiency virus or HIV for this virus], or related retroviruses. The reagents to be produced by this contractor include pools of virus material that can be used as standards, monoclonal and polyclonal antisera, and purified viral components such as the envelope glycoprotein or the reverse transcriptase. The contractor is also prepared to produce these reagents from related retroviruses, such as STLV-III, as needed by the AIDS Program. These reagents will be made available to intramural and extramural investigators.